Date of Award


Degree Name

Master of Arts



First Advisor

John A. Tanis

Second Advisor

Dr. Robert Shamu

Third Advisor

Dr. Roger Haar

Access Setting

Masters Thesis-Open Access


Non-resonant Transfer and Excitation (NTE) by 20-70 Mev S,3+ projectiles in collisions with neutral gas targets of He, Ne and Ar is investigated. For NTE, positively charged projectiles undergo excitation and electron capture in a single collision in which the capture and excitation processes are independent events. The mechanisms involved in the NTE process are electron-nucleus interactions, and the combination of projectile excitation and capture is a two-step process. In this work, NTE cross sections, along with total K x-ray production cross sections and total single-electron capture and loss cross sections, were measured as a function of projectile energy. The results are used to establish the dependence of NTE on the atomic number of the target. The present results for S13+ incident on He are consistent with the results of Tanis et al. (1985) which indicate that a maximum in the NTE cross section occurs at about 3 0 MeV. It is found here that for Ne and Ar the maximum NTE cross section occurs at about 50 MeV and 60 MeV, respectively. Thus, with increasing target atomic number, NTE occurs for higher projectile energies.

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